1. Field of the Invention
This invention relates to improvements in artificial intraocular lenses (pseudophakoi) and has particular reference to the manufacture of perforate optical sections (lenses) of pseudophakoi to which haptic sections (iris clips) may be fitted.
2. Discussion of the Prior Art
Well-fixed and well-centered intraocular lens implants are known to produce stable retinal images and offer the best chance of re-establishment of binocularity in cases of aphakia.
Many techniques of lens implantation, including suturing to the ciliary muscle as disclosed in U.S. Pat. No. 3,711,870 and iris diaphragm fixation as discussed in U.S. Pat. No. 3,673,616 for example, have been used. The latter is considered to be a safe procedure giving good stability and the present invention deals more particularly with improvements in this general type of pseudophakos but also has applicability to the former and/or any other type of pseudophakos requiring the provision of holes in its lens through which sutures may be extended or within which iris clips or other fastening wires may be inserted and anchored.
In cases of iris diaphragm fixation, "iridocapsular" and/or "iris clip" pseudophakoi are used. These implants are provided with a fastening section comprised of posterior and/or anterior iris clips usually in the form of loops or struts of wire or wire-like material, the ends of which are anchored in holes provided in the lens of the pseudophakos.
In view of a requirement for carefully controlled exceptionally close tolerances of hole size and the minuteness required of such holes, e.g. from 0.1 to 0.2 mm for lenses having a full diameter of only approximately 4 mm, the practice heretofore of forming such holes with drills has presented serious problems of tediousness, high scrap yield and excessive product cost, not to mention other adversities such as roughness or incipient cracking of lens material within the holes and/or chipping or flaking adjacent or at opposite ends of the holes, all of which tend to weaken the lens structure and render it subject to damage when wire iris clips and the like are anchored therein.
It has also been a practice heretofore to extend iris clip anchoring holes in directions parallel to a lens axis and completely through the lens with the disadvantage of interrupting the otherwise smooth contour of the anterior surface of the lens. Holes extending through the front surface of a lens can interfere with lens insertion, trap tissue or fluids or otherwise be adverse to the acceptance and/or function of a pseudophakos.
A principal object of the present invention is to provide pseudophakoi of improved construction and more particularly to provide a novel lens structure and method for manufacturing perforated lenses of pseudophakoi; another object is to provide for the manufacture of tengentially perforated artificial intraocular lenses in an unusually simple, rapid and economical manner wherewith manufacturing output can be readily maximized at minimum product cost with improved product quality and dependability of duplication in mass production; and still another object is to provide a lens of unique peripheral configuration and having smooth uninterrupted anterior and posterior surfaces.